Running the "Dog Food" stats on your new TFS 2010 server is a good way to see if the upgrade was successful. You should check the new values against the stats you noted down from your TFS 2008 server.
-- Files:
1 28052
2 335168
-- Compressed file size:
11837952896
-- Uncompressed file sizes:
24868196032
-- Areas & Iterations:
1096
Figure: Have a look at the dogfoodstats you ran before
-- Areas and Iterations:
1096
-- Files:
347629
-- Compressed File Sizes:
11296
-- Uncompressed File Sizes:
23723
Figure: You should get the same number or more for your TFS2010 server. We’re not worried unless it’s slightly less